First off, I'm very intrigued by the possibilities of Hairy_Hen's new process, so I'm completely in support of waiting for his results. When it comes to DTS-HD MA or Dolby TrueHD, DTS-HD MA almost seems to be the go to standard by most studios, I'm actually rather surprised whenever I see a disc that goes with Dolby TrueHD. So, whether it has the best support or not (and many of the dirt cheap Blu-ray players only seem to do stereo decoding for DTS-HD MA), DTS-HD MA may be the more 'professional' route to go with.
IMO the studios go with DTS-HD MA because there aren't open source decoders available for it and therefore it is more difficult to playback in full resolution, thus thwarting 1:1 copying to some degree. The media player manufacturers also frequently prevent bitstreaming of DTS-HD MA thus making full resolution playback of copies more difficult. The same can not be said of TrueHD.
I think even the cheap Bluray players will bitstream DTS-HD MA or decode to multichannel LPCM via HDMI. The whole point of HDMI/HDCP was to protect the high resolution from capture and perfect duplication by "pirates" and in that respect it is successful, so there is no point crippling that output. I'm not sure if the cheap players only use the DTS core via HDMI, but I think it unlikely.
We must remember that lossless encoding says nothing about the quality of the source: one can losslessly encode a 128kbps AC3 source to TrueHD but it will still sound crap. Lossless encoding merely retains the existing quality of the source. Lossy encoding can still be perfectly adequate if the source was lossily encoded at a lower bitrate somewhere in its history.
Therefore, I think any release should have a lossless encode plus a high bitrate lossy encode of the competing audio format, for the highest quality source, as a minimum, to provide maximum consumer compatibility; plus all soundtracks offered separately in lossless and lossy (both formats) depending on source quality for consumer selection. This may mean DTS-HD MA plus DD 640 for the primary soundtrack.